Carboxylation products of alk(en)yl oligoglycosides are anionic surfactants which have improved foaming, viscosity and sensory properties in relation to the non-derivatized homologs. They are normally produced by reaction of the glycosides with halocarboxylic acid salts, especially sodium chloroacetate, in aqueous solution. Some or all of the hydroxyl groups available are reacted, depending upon the quantity of alkylating agent used. Since this reaction generally requires an excess of the alkylating agent, the end products always contain traces of organic chlorine compounds which can amount to as much as 2,000 ppm, based on monochloroacetate for example, or to as much as 500 ppm, based on the dichloroacetate present as an impurity in the monochloroacetate.
For cosmetic applications in particular, such quantities of organo-chlorine compounds are unacceptable because they can cause irritation of the skin or are otherwise undesirable for physiological reasons.
Accordingly, the problem addressed by the present invention was to provide an improved process for the production of alk(en)yl oligoglycoside carboxylic acid salts which would give products with a content of organochlorine compounds of less than 35 ppm and preferably less than 10 ppm.